1. Field of the Invention
The present invention relates to a platinum (II) complex. More particularly, the present invention pertains to a platinum (II) complex having excellent antibacterial activity and anticancer activity, in particular, effective to use as an anticancer agent and a process for preparing the same.
2. Description of the related Art
Recently, a remarkable development has been achieved in medical and pharmaceutical fields, and as a result, diseases conventionally considered to be incurable and showing a high mortality have been protected, restrained or cured (or recovered) to a substantial degree. Under such circumstances, cancer has drawn a great attention because of its high mortality. However, up to now, there has not yet been proposed an effective solution to reduce the mortality of patients suffering from cancer.
There have been proposed conventional therapeutics for cancer, such as surgical operation in which the affected part of patients is cut off, irradiation (radiotherapy), chemical therapy (chemotherapy) by administering medicines. Recently, the immunological therapy (immunotherapy), the interferon therapy, and the utilization of laser such as YAG laser as new technique of the surgical operation have drawn a great attention.
However, the surgical operation and the radiotherapy among others are a kind of locally applied techniques of therapy and are effective means for treating patients only if the disease is in its primitive state or there is not metastasis, while these therapeutics are not effective against the progressive cancer i.e., those accompanying metastasis in the whole body of patients as well as the systematic diseases such as leukemia and malignant lymphoma in which a specific system in the whole body is gradually affected. On the other hand, the chemotherapy is the only effective therapeutics against the latter systematic diseases and some of the cancer may be cured by the chemical therapy. It is also recognized that the chemotherapy is an effective tool for treating patients suffering from cancer, in particular, when it is applied as an additional or auxiliary treatment after the surgical operation or it is applied in combination with the radiotherapy and thus, this is one of the therapeutic technique in which a great future development is expected.
Up to now, various kind of anticancer agents have been developed and proposed and each of them differs in its property and the effectiveness thereof varies depending on the kind of cancer. There may be mentioned such as mitomycin C, adriamycin as the medicine against adenocarcinoma (carcinoma in digestive organs, oophoroma); vincristine, bleomycin against the malignant lymphoma; cytocine arabinoside, L-asparaginase for acute leukemia.
The chemotherapy for the cancer is based on the fact that the cancer may be caused by the parasite such as cancer cells in a human body as encountered in the case of bacteria in the general infectious diseases. In other words, the cancer cells are considered to be normal cells which are converted to a variant by some causes and the variant once formed in a body is considered to be the parasite exhibiting autonomous proliferation.
Although cancer cells and normal cells are different in their biological and biochemical properties from each other, the difference is simply in a quantitative one, while the qualitative difference between them has not yet been made clear. Therefore, the normal cells may possibly be impaired by the action of chemical agents (medicine) in the chemotherapy and this is revealed as so-called side-effects due to the medicine (such as anticancer agents). Thus, it is quite difficult to restrain only the proliferation of cancer cells or destroy only these cells utilizing such medicines.
As seen from the above, the development of a new technique for treating cancer is a principal subject to be solved in the medical and pharmaceutic fields and an absolute therapy therefor should be developed. However, it can not be expected to achieve a new drastic development in the surgical therapy and the radiotherapy. Thus, it is more preferable or practical to improve chemotherapy or to develop a new medicine since a significant future development may be expected. It is expected, in particular, as the additional or auxiliary treatment means after the surgical operation of the affected part and it may be used in combination with the radiotherapy. Furthermore, the chemotherapy may be an effective tool for treating the progressive cancer as well as the systematic diseases. Thus, there is a great need to develop a new therapeutic technique in medical or pharmaceutical science to remedy the patients suffering from these diseases. It must be said, however, that such agents should fulfill such requirement that they affect on the cancer cells specifically and selectively.
An object of this invention is to provide a novel platinum (II) complex having no side-effects which affects on cancer cells specifically and selectively.
An other object of this invention is to provide a method for preparing the platinum (II) complex.